Sharif University of Technology Scientia Iranica 1026-3098 22 3 2015 06 01 Measuring wave velocity, damping and stress-strain behaviors of geo-materials using GAP-SENSOR Measuring wave velocity, damping and stress-strain behaviors of geo-materials using GAP-SENSOR 679 698 1895 EN A. Aghaei Araei Department of Geotechnical Engineering, Road, Housing and Urban Development (BHRC), Tehran, P.O. Box 13145-1696, Iran A. Aghaei Araei Department of Geotechnical Engineering, Road, Housing and Urban Development (BHRC), Tehran, P.O. Box 13145-1696, Iran I. Towhata Geotechnical Engineering Group, Department of Civil Engineering, University of Tokyo, 7-3-1 Hongo Bunkyo-ku, Tokyo, P.O. Box 113-8656, Japan S. Hashemi Tabatabaei Department of Geotechnical Engineering, Road, Housing and Urban Development (BHRC), Tehran, P.O. Box 13145-1696, Iran H.R. Razeghi School of Civil Engineering, Iran University of Science and Technology (IUST), Tehran, P.O. Box 16765-163, Iran S. Hashemi Tabatabaei Department of Geotechnical Engineering, Road, Housing and Urban Development (BHRC), Tehran, P.O. Box 13145-1696, Iran Journal Article 2015 06 30 A triaxial testing system is described for measuring the wave velocity, stiness, damping and stress-strain behavior of layered granular materials and rock specimens under impact, cyclic and monotonic loading. The system is equipped with high-frequency GAPSENSORs (GSs) in front of target plates connected on the side of a specimen surface to measure wave velocity, axial and radial deformations locally, LDTs to measure axial and radial deformations locally, and a load cell. Based on the rst arrival of compressional wave of the deformation time-histories under impact loading, the pulse velocity is evaluated. In addition, using a reduced deformation amplitude technique at dierent elevations of the specimen, damping ratio is calculated. Results indicate that measurement of the wave velocity and damping ratio using low noise level GSs is a simple,  nondestructive and reproducible method. Comparing the results of small strain shear modulus and damping ratio using local axial and radial strains measured by LDTs and GSs in the cyclic loading, with those of the proposed method, the high precision of the used innovative method is conrmed. Using this system, a continuous stress-strain relation for a strain range of 0.0001% to several % can be obtained fro  a single test using a single specimen. https://scientiairanica.sharif.edu/article_1895_7c7861852fad58ad59e2bbd370de3c6e.pdf